No exploitation reported

CVE-2018-1000831

Q: What is CVE-2018-1000831?

K9Mail version <= v5.600 contains a XML External Entity (XXE) vulnerability in WebDAV response parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This attack appear to be exploitable via malicious WebDAV server or intercept the reponse of a valid WebDAV server.

Q: Is CVE-2018-1000831 actively exploited?

Active exploitation of CVE-2018-1000831 has not been confirmed. Its EPSS score was 1.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2018-1000831?

CVE-2018-1000831 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2018-12-20
WeaknessCWE-611

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

K9Mail version <= v5.600 contains a XML External Entity (XXE) vulnerability in WebDAV response parser that can result in Disclosure of confidential data, denial of service, SSRF, port scanning. This attack appear to be exploitable via malicious WebDAV server or intercept the reponse of a valid WebDAV server.

Timeline

dates in UTC

2018-12-2015:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-1000831?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-1000831?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

K9mail k-9 mail

Branch	Affected	Fixed in	Source
5.600	≤ 5.600	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.010read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-611read 2026-10-23
FIRST EPSSEPSS score1.9 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published: 2018-12-20
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2018-1000831?

Is CVE-2018-1000831 actively exploited?

Active exploitation of CVE-2018-1000831 has not been confirmed. Its EPSS score was 1.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-1000831?

CVE-2018-1000831 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

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